Table Of Contents

Open Tag (G Dataflow)

Version:
    Last Modified: August 7, 2018

    Opens a reference to a tag on the server. If no reference of the tag exists on the server, the node creates one.

    Programming Patterns
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    configuration

    Connection established with the server.

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    path

    Path to tag reference.

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    Note  

    Tag paths do not support spaces. If an illegal character is present, the node errors out.

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    data type

    Data type of the tag reference.

    If a tag with the same path but different data type already exists, Open Tag returns an error. Use Query Tags to open existing tag references of unknown data types.

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    error in

    Error conditions that occur before this node runs.

    The node responds to this input according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Default: No error

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    tag out

    Tag the server referenced to communicate measurement data.

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    error out

    Error information.

    The node produces this output according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Using an Asterisk in a Tag Path

    To set tag permissions for a group of tags or query a collection of tags, use an asterisk to match any sequence of zero or more characters in a tag path. For example, to return every tag that begins with example.path on the web server, enter example.path* in to the path input.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported

    Web Server: Supported in VIs that run in a web application


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